Patent (U.S. Pat. No. 7,638,645) discloses compounds containing metals in the +4 oxidation state bonded to four amidinate ligands, the broad disclosure of metals which includes tellurium. The metal tetra-amidinate compounds may be used to form metal-containing films in a vapor deposition process, exemplary deposition methods being CVD and ALD. The process includes exposing the substrate to a source of nitrogen, and the thin film comprises a metal nitride. The source of nitrogen comprises ammonia.
Patent application (EP2000561A1) discloses formamidinate compounds wherein the metal is chosen from a Group 2 to Group 16, the broad disclosure of which includes Te and Se. It discloses that the numerous formamidinate compounds may be used in ALD and CVD processes to deposit metal or metal oxide or metal nitride or metal silicate or metal silicon oxynitride thin films. The method for depositing films permits the use of a second precursor, the second precursor being any precursor that reacts with the first precursor. Oxygen, ozone, water, peroxide, alcohols, nitrous oxide and ammonia are mentioned as exemplary second precursors.
Document (US2009/137100) discloses a method of forming tellurium-containing film, wherein a silyltellurium precursor is used as a source of tellurium for the alloy film and is reacted with an alcohol during the deposition process using chemical vapor deposition methods at low temperatures. The tellurium precursor being selected from the group consisting of (R1R2R3Si)2Te, (R1R2R3Si)TeR4, (R1R2R3Si)TeN(R4R5) where R1, R2, R3, R4 and R5 are individually hydrogen, alkyl groups with 1 to 10 carbons in linear, branched or cyclic form, or an aromatic group. An alcohol with the general formula ROH where R is an alkyl group with 1 to 10 carbon atoms in linear, branched, or cyclic form or an aromatic group, is to be reacted with tellurium precursor to form a tellurium layer. Tellurium nitride films can not be obtained with this method.
Patent application (WO2011/056519) mentions ALD processes for forming Group VA element containing films. Among other processes, ALD for forming nitrogen-containing thin films is provided. In that particular case, the vapor phase reactant N-source may have the formula [N(AR1R2R3)xR3-x], [N[A1(X1R1R2R3)3][A2(X2R4R5R6)3][A3(X3R7R8R9)3]] or [N[A1(X1R1R2R3)3][A2(X2R4R5R6)3]H]; wherein x is from 1 to 3, A is Si, Ge or Sn and R1-9 can be independently selected to be linear, cyclic, branched or substituted alkyl, alkenyl, alkynyl, hydrogen or ayrl groups. In some embodiments, R1-R9 can be any organic groups containing heteroatoms or can be a halogen atoms. X1-3 can be Si, Ge, N or O. Selected examples of N-containing precursors are N(SiMe2tBu)3, N(SiH3)3, N(SiEt3)3 or N(SiMe3)3. The N-containing precursors may be used in combination with metal precursors selected from the group consisting of elements from Group IIIA to VIA. Concretely, the authors focus on BN, AlN, GaN films.
In particular, they can be used in combination with Te and Se precursors. Te and Se precursors may have the formula A(SiR1R2R3)2, [R1R2R3X1]3—Si-A-Si—[X2R4R5R6]3, R1R2R3Si—Si-A-Si—SiR4R5R6, R1 R2N—Si-A- Si—NR3R4, R1OSi-A-SiOR2, or R1R2Si-A-SiR3R4; wherein A is Te or Se and R1, R2, R3, R4, R5 and R6 are hydrogen, alkyl groups comprising one or more carbon atoms, alkenyl, alkynyl or aryl groups, organic groups containing hydrogen atoms, halogen atoms and X1, X2 can be Si, O, N. Selected examples are Se(SiMe2tBu)2, Te(SiEt3)2, Te(SiMe3)2, Se(SiEt3)2 or Se(SiMe3)2. In other embodiments, the Te and Se precursors may also have multiple atoms of Si and Te or Se.
Patent application (US2009/256127) discloses tellurium metal-organic compounds with the general formula {RTe-L,} where R represents either substituted β-diketiminato ({R′C(NR)CRC(NR)R}) or β-ketoiminato ({R′COCR C(NR)R}) ligands, wherein R′ and R may be the same or different and represent a linear or branched C1-C5 alkyl, halogen-substituted linear or branched C1-C7 alkyl, a C1-C4 alkylamide, a C1-C4 alkoxide, an aryl substituted phenyl, or an organosilyl; and each L is independently selected from the group consisting of a hydrocarbon, an oxygen-containing hydrocarbon, a nitrogen-containing hydrocarbon, an amine or polyamine, a bipyridine, a heterocycle containing oxygen or nitrogen, or any combination thereof. It discloses the use of such complexes for the deposition of tellurium nitride, the nitrogen source being ammonia, hydrazine and alkyl derivatives, containing radicals (for instance N., NH., NH˜.), NO, N˜O, NO˜, amines, and any combination thereof.
Patent application (US2009/299084) discloses tellurium metal-organic compounds with the general formulas {(XR1R2R3)Te(XR4R5R6)}, {(—(R1R2X)nTe—}y)}, {(—(R1R2X)nTe(XR3R4)m)Te—)y)}, {Te(XNR1CR2R3CR4R5NR6)}, {Te(XNR1CR2═CR3NR4)}, wherein X is a carbon, silicon or germanium atom, n,m are selected from 0 to 2, each R1-6 is independently selected from among H, a C1-C6 alkyl, a C1-C6 alkoxy, a C1-C6 alkylsilyl, a C1-C6 perfluorocarbon, a C1-C6 alkylsiloxy, a C1-C6 alkylamino an alkylsilylamino and an aminoamido; and the use of those precursors onto the substrate to form a tellurium containing film with H2, NH3, hydrogen radicals; and mixtures thereof as co-reactant.
A need remains for chalcogenide-containing precursor molecules suitable for vapor phase film deposition in thermal mode at low temperatures.